AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40
  DESPEC  ELOG logo
Message ID: 69     Entry time: Wed Oct 30 11:51:08 2019
Author: CA, TD, NH 
Subject: Detector biasing 
12.51 - detector bias and leakage currents - detector 3 has no current
                                           - other detectors ok

13.13 - tried changing from HV3 cables to HV4 - still open circuit 

      - tried different permutations of moving HV-4 braid and core cables (high voltage to ground connections)

       (dssd3)

      (all directions defined as if looking upstream)

      - core -> bottom, braid -> left     open - circuit

      - core -> top, braid -> right       trips at 8V

      - core -> bottom, braid -> right     open - circuit

      - core -> top, braid-> left          trips at 8V

      - removed jumpers - still trips

13.36 - testing continuity of bond wires on dsssd 3208-14 & 3208-15

      - observe 20 ohm resistance on p+p and p+n bond wires 

19:41 - dsssd 1 and 2 not biasing, 3 ok.

      - changed bias configuration -> HV core 1 & 2 now on top, braid on right

      - ribbon cables for DSSSD #1 & #2 p+n junction strips down were misaligned

      - all detectors biased succesfully

HV cable configuration (looking upstream): HV-1 Core -> top-inner (FEE 1)
                        
                                           HV-2 Core -> top-middle (FEE 5)

                                           HV-3 Core -> bottom-outer (FEE 11)

                                           HV-1 Braid -> right-inner (FEE 2)

                                           HV-2 Braid -> right-middle (FEE 6)

                                           HV-3 Braid -> left-outer (FEE 12)

Attachment 3 - rough sketch of HV cable configuration, looking upstream.
       
Attachment 1: bias30Oct.png  13 kB  | Hide | Hide all
bias30Oct.png
Attachment 2: 30Octbias2.png  12 kB  Uploaded Wed Oct 30 18:40:53 2019  | Hide | Hide all
30Octbias2.png
Attachment 3: hvsketch.pdf  118 kB  Uploaded Thu Oct 31 09:28:42 2019  | Hide | Hide all
hvsketch.pdf
ELOG V3.1.4-unknown